Aluminum heat exchangers are manufactured by a brazing method in which the mating aluminum parts, tubes, cooling fins, and the like, are coated with a braze material that melts and liquifies at a temperature lower than the melting point of the base aluminum. Wherever a small, controlled gap exists, as between a slot in a tank header plate and the end of a tube in the slot, melted braze material is drawn in by capillary action to create a braze seam that becomes rigid and leak free upon later cooling and solidification. To aid in the process, the workpiece is first flux coated, a layer that also melts when heated. Oxygen would chemically interfere with the braze process if it were present, so it is standard practice to provide a controlled inert gas environment within the braze furnace, which is usually nitrogen, since it is nontoxic and relatively easy to handle. However, nitrogen must be stored in a liquid form in bulk, and must be vaporized before it is used in the brazing process. Therefore, some apparatus must be provided to vaporize it. Typically, liquid nitrogen is run through a separate evaporator and preheater before it is ducted into the braze furnace. In addition, braze furnaces, such as that disclosed in U.S. Pat. No. 5,172,847 often contain a separate means, such as a water jacket, to actively cool the brazed workpiece before it is withdrawn back into the atmosphere.